/* Copyright (C) 2021,2022 fef <owo@fef.moe>.  All rights reserved. */

#pragma once

#include <arch/poison.h>

#include <limits.h>

/*
 * If possible, arch should define this value as an unmappable base address.
 * For example, on the amd64, this is set to 0xdead000000000000 because the
 * highest 17 bits of linear addresses must always be identical there.
 * As a result, it will *always* page fault when dereferenced, no matter
 * the current state of the page maps.
 */
#ifndef POISON_BASE
#define POISON_BASE 0ul
#endif

/*
 * You should only use values that `sus_nil()` finds sus (i.e. values < 0x1000),
 * and whose LSB is zero.  The latter is a little safety measure because most
 * architectures use bit 0 of the page maps as a present flag.  So, even if the
 * impossible happens and this *somehow* ends up in a page map, it is marked as
 * non-present and therefore page faults rather than exposing anything.
 */

#define PAGE_POISON_ALLOC	(POISON_BASE + 0x00000010ul)
#define PAGE_POISON_FREE	(POISON_BASE + 0x00000020ul)

#if LONG_BIT == 32
#define SLAB_POISON_ALLOC	0x61616160ul
#define SLAB_POISON_FREE	0x41414140ul
#elif LONG_BIT == 64
#define SLAB_POISON_ALLOC	0x6161616161616161ul
#define SLAB_POISON_FREE	0x4141414141414141ul
#elif LONG_BIT == 128
#define SLAB_POISON_ALLOC	0x61616161616161616161616161616160ul
#define SLAB_POISON_FREE	0x41414141414141414141414141414140ul
#else
#error "Unsupported long size"
#endif

#define CLIST_POISON_PREV	(POISON_BASE + 0x000000c4ul)
#define CLIST_POISON_NEXT	(POISON_BASE + 0x000000c8ul)